Economic Evaluation of Sacituzumab Govitecan for the Treatment of Metastatic Triple-Negative Breast Cancer in China and the US

Revolutionizing triple-negative metastatic breast cancer treatment: sacituzumab Govitecan's role in advancing chemotherapy

Purpose

This review aims to discuss the role and efficacy of Sacituzumab Govitecan in the management of breast cancer.

Summary

Breast cancer is the most prevalent type of cancer among women worldwide. This comprehensive review delves into the advancements brought about by Sacituzumab Govitecan in the treatment of metastatic triple-negative breast cancer (TNBC). With a focus on its mode of action, efficacious role, clinical trials, and comparative advantages over conventional chemotherapy, the review highlights the therapy's precision in targeting cancer cells through monoclonal antibodies. Sacituzumab Govitecan's ability to deliver a chemotherapeutic payload specifically to cancer cells with the Trop-2 receptor sets it apart from traditional chemotherapy, minimizing collateral damage and reducing severe side effects. The impact of Sacituzumab Govitecan on improving progression-free survival, tumor response rates, and, significantly, the quality of life for patients is discussed. This article also sheds light on ongoing trials, FDA recognition, and the therapy's potential to transform breast cancer treatment.

Conclusion

In conclusion, Sacituzumab Govitecan shows potential as an innovative therapeutic option for breast cancer, particularly in metastatic breast cancer and triple-negative breast cancer, but it warrants additional research.

Cost-effectiveness of sacituzumab govitecan versus single-agent chemotherapy for metastatic triple-negative breast cancer: a trial-based analysis

BACKGROUND

Sacituzumab govitecan (SG) has recently been approved in China for the post-line treatment of metastatic triple-negative breast cancer (mTNBC). SG substantially improves progression-free survival and overall survival compared with single-agent chemotherapy for pretreated mTNBC. However, in view of the high price of SG, it is necessary to consider its value in terms of costs and outcomes. This study aimed to estimate the cost-effectiveness of SG versus single-agent treatment of physician's choice (TPC) in the post-line setting for patients with mTNBC from a Chinese healthcare system perspective.

METHODS

The cohort characteristics were sourced from the ASCENT randomized clinical trial, which enrolled 468 heavily pretreated patients with mTNBC between November 2017 and September 2019. A partitioned survival model was constructed to assess the long-term costs and effectiveness of SG versus TPC in the post-line treatment of mTNBC. Quality-adjusted life-months (QALMs) and total costs in 2022 US dollars were used to derive incremental cost effectiveness ratio (ICER). QALMs and costs were discounted at 5% annually. The willingness-to-pay (WTP) threshold was defined as $3188 per QALM, three times China's average monthly per capita gross domestic product in 2022. One-way sensitivity analysis, probabilistic sensitivity analysis, and scenario analyses were performed to estimate the robustness of the results.

RESULTS

Treatment with SG yielded an incremental 5.17 QALMs at a cost of $44,792 per QALM, much above the WTP threshold of $3188/QALM in China. One-way sensitivity analysis showed that SG price was a crucial factor in the ICER. Probabilistic sensitivity analysis revealed that the cost-effective acceptability of SG was 0% in the current setting. Scenario analyses indicated that the result was robust in all subgroups in ASCENT or under different time horizons. Furthermore, SG must reduce the price to enter the Chinese mainland market. When the monthly cost of SG reduce to $2298, SG has about 50% probability to be a preferred choice than TPC.

CONCLUSIONS

SG was estimated to be not cost-effective compared with TPC for post-line treatment for mTNBC in China by the current price in HK under a WTP threshold of $3188 per QALM. A drastic price reduction is necessary to improve its cost-effectiveness.

Cost-benefit evaluation of advanced therapy lines in metastatic triple-negative breast cancer in Germany

BACKGROUND

Triple-negative breast cancer (TNBC) is responsible for 10-20% cases of breast cancer and is resulting in rising healthcare costs. Thus, health-economic evaluations are needed to relate clinical outcomes and costs of treatment options and to provide recommendations of action from a health-economic perspective.

METHODS

We investigated the cost-benefit-ratio of approved treatment options in metastatic TNBC in Germany by applying the efficiency frontier approach. These included sacituzumab-govitecan (SG), eribulin, vinorelbine, and capecitabine. Clinical benefit was measured as (i) median overall survival (mOS) and (ii) health-related quality of life (HRQoL) in terms of time to symptom worsening (TSW). To assess medical benefits, literature was systematically reviewed in PubMed for (i) and (ii), respectively. Treatment costs were calculated considering annual direct outpatient treatment costs from a statutory healthcare payer perspective. It was intended that both, (i) and (ii), yield an efficiency frontier.

RESULTS

Annual direct outpatient treatment costs amounted to EUR 176,415.21 (SG), EUR 47,414.14 (eribulin), EUR 13,711.35 (vinorelbine), and EUR 3,718.84 (capecitabine). Systematic literature review of (i) and statistical analysis resulted in OS values of 14.3, 9.56, 9.44, and 7.46 months, respectively. Capecitabine, vinorelbine, and SG are part of the efficiency frontier including OS. The highest additional benefit per additional cost was determined for vinorelbine, followed by SG. Systematic review of (ii) revealed that no TSW data of TNBC patients receiving vinorelbine were available, preventing the presentation of an efficiency frontier including HRQoL.

CONCLUSIONS

Vinorelbine is most cost-effective, followed by SG. Health-economic evaluations support decision-makers to assess treatment options within one indication area. In Germany, the efficiency frontier can provide decision support for the pricing of innovative interventions. Results of our analysis may thus guide reimbursement determination.

Cost-utility analysis of sacituzumab govitecan versus chemotherapy for the treatment of metastatic triple-negative breast cancer in Singapore

OBJECTIVE

To assess the cost-effectiveness of sacituzumab govitecan for treating relapsed or refractory metastatic triple-negative breast cancer (TNBC) in Singapore.

METHODS

A three-state partitioned survival model was developed to evaluate the cost-effectiveness of sacituzumab govitecan from a healthcare system perspective over 5 years. Clinical inputs were obtained from the ASCENT trial. Health state utilities were retrieved from the literature and direct costs were sourced from public healthcare institutions in Singapore. Sensitivity and scenario analyses were conducted to explore the impact of uncertainties and assumptions on cost-effectiveness results.

RESULTS

Compared with single-agent chemotherapy, sacituzumab govitecan was associated with a base-case incremental cost-effectiveness ratio (ICER) of S$328,000 (US$237,816) per quality-adjusted life year (QALY) gained. One-way sensitivity analyses showed that the ICER was most sensitive to the cost of sacituzumab govitecan and progression-free utility values. Regardless of variation in these parameters, the ICER remained high, and a substantial price reduction was required to reduce the ICER.

CONCLUSION

At its current price, sacituzumab govitecan does not represent a cost-effective treatment for relapsed or refractory metastatic TNBC in Singapore. Our findings will be useful to inform funding decisions alongside other factors including clinical effectiveness, safety, and budget impact considerations.

Advances in the study of marketed antibody-drug Conjugates (ADCs) for the treatment of breast cancer

Breast cancer continues to have a high incidence rate among female malignancies. Despite significant advancements in treatment modalities, the heterogeneous nature of breast cancer and its resistance to various therapeutic approaches pose considerable challenges. Antibody-drug conjugates (ADCs) effectively merge the specificity of antibodies with the cytotoxicity of chemotherapeutic agents, offering a novel strategy for precision treatment of breast cancer. Notably, trastuzumab emtansine (T-DM1) has provided a new therapeutic option for HER2-positive breast cancer patients globally, especially those resistant to conventional treatments. The development of trastuzumab deruxtecan (T-DXd) and sacituzumab govitecan (SG) has further broadened the applicability of ADCs in breast cancer therapy, presenting new hopes for patients with low HER2 expression and triple-negative breast cancer. However, the application of ADCs presents certain challenges. For instance, their treatment may lead to adverse reactions such as interstitial lung disease, thrombocytopenia, and diarrhea. Moreover, prolonged treatment could result in ADCs resistance, complicating the therapeutic process. Economically, the high costs of ADCs might hinder their accessibility in low-income regions. This article reviews the structure, mechanism of action, and clinical trials of commercially available ADCs for breast cancer treatment, with a focus on the clinical trials of the three drugs, aiming to provide insights for clinical applications and future research.

Cost-effectiveness of trastuzumab deruxtecan in previously treated human epidermal growth factor receptor 2-low metastatic breast cancer

Background

Results from DESTINY-Breast04 trial revealed that trastuzumab deruxtecan (T-DXd) improved both progression-free survival and overall survival for patients with human epidermal growth factor receptor 2 (HER2)-low metastatic breast cancer (mBC). However, the economic impact of this practice remains unclear. The purpose of this study was to evaluate the cost-effectiveness of T-DXd on HER2-low mBC from the viewpoint of U.S. payers.

Methods

Using the clinical data from the DESTINY-Breast04 trial, a three-state Markov model was created to assess the economic and health effects of T-DXd versus chemotherapy. The incremental cost-effectiveness ratio (ICER) and willingness-to-pay threshold were determined and compared. One-way and probabilistic sensitivity analysis were used to measure parameter uncertainty.

Results

In the overall HER2-low population, T-DXd provided additional 0.47 quality-adjusted life-years (QALYs) at an increased cost of $149,222 compared with chemotherapy, yielding an ICER of $317,494/QALY. The ICER was $353,903/QALY in the hormone receptor (HR)-positive subgroup, which decreased to $259,825/QALY in the HR-negative subgroup. The sensitivity analysis found that T-DXd would not be cost-effective in the base-case. The expected cost of T-DXd will be less than $4,281/cycle ($11.33/mg) or $1,903/cycle ($5.03/mg) to achieve a 50 or 90% cost-benefit probability, respectively.

Conclusions

T-DXd provides significant health benefit for patients with HER2-low mBC compared with chemotherapy but is unlikely to be cost-effective in the United States.

Cost-effectiveness of sacituzumab govitecan in hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer

Background

The efficiency and safety of sacituzumab govitecan (SG) for the therapy of hormone receptor-positive (HR+)/human epidermal receptor 2-negative (HER2-) metastatic breast cancer (BC) has been demonstrated. The aim of this study is to evaluate its cost-effectiveness on HR+/HER2- metastatic BC from the third-party payer perspective in the United States.

Methods

We performed the cost-effectiveness of SG and chemotherapy using a partitioned survival model. TROPiCS-02 provided clinical patients for this study. We evaluated the robustness of this study by one-way and probabilistic sensitivity analyses. Subgroup analyses were also conducted. The outcomes were costs, life-years, quality-adjusted life years (QALYs), incremental cost-effectiveness ratio (ICER), incremental net health benefit (INHB), and incremental net monetary benefit (INMB).

Results

SG treatment was related to an increase of 0.284 life years and 0.217 QALYs over chemotherapy, as well as a cost increase of $132,689, reaching an ICER of $612,772/QALY. The INHB was -0.668 QALYs, and the INMB was -$100,208. SG was not cost-effective at the willingness to pay (WTP) threshold of $150,000/QALY. The outcomes were sensitive to patient body weight and cost of SG. SG may be cost-effective at the WTP threshold of $150,000/QALY if the price is less than $3.997/mg or the weight of patients is under 19.88 kg. Based on the subgroup analysis, SG did not prove cost-effective in all subgroups at the WTP threshold of $150,000/QALY.

Conclusion

From a third-party payer standpoint in the United States, SG was not cost-effective, even though it had a clinically significant advantage over chemotherapy for the treatment of HR+/HER2- metastatic BC. The cost-effectiveness of SG can be improved if the price is substantially reduced.

Cost-effectiveness analysis of trastuzumab deruxtecan versus trastuzumab emtansine for HER2-positive breast cancer

Background: The DESTINY-Breast03 clinical trial demonstrated that trastuzumab deruxtecan (T-DXd) outperformed trastuzumab emtansine (T-DM1) in progression-free survival (PFS) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC). Considering the excessive cost of antibody-drug conjugates, the clinical value of T-DXd must be assessed by both its efficacy and cost. We compared the cost-effectiveness of T-DXd and T-DM1 for patients with HER2-positive mBC pretreated with anti-HER2 antibodies and a taxane from the perspectives of the United States (US) and China.

Methods: A comprehensive Markov model based on the DESTINY-Breast03 phase III randomized clinical trial was used to compared the cost and effectiveness of T-DXd and T-DM1 for HER2-positive mBC. Data on direct medical cost and utilities were collected from published literatures. The recorded data included the costs, quality-adjusted life-year (QALY), incremental cost-effectiveness ratio (ICER) and incremental net-health benefit (INHB). Sensitivity analysis was conducted to measure the potential uncertainty due to parameter variability. Additional subgroup cost-effectiveness analysis was performed.

Results: Treatment of HER2-positive mBC with T-DXd gained 0.73 QALYs compared with T-DM1 strategy. The incremental cost was $59,942 in the US, with an ICER of $ 82,112/QALY and an INHB of 0.33 QALYs, respectively. In China, the incremental cost of T-DXd versus T-DM1 was $222,680, with an ICER of $305,041/QALY and a negative INHB of -5.18 QALYs. At willingness-to-pay (WTP) threshold of $150,000/QALY in the US and $37,653/QALY in China, the probability of T-DXd as the dominant option was 77.5 and 0.1%, respectively. The unit price of T-DXd greatly influenced the results according to one-way sensitivity analysis. To meet the 50% or 90% chance of being cost-effective, the estimated cost of T-DXd would need to be less than $17.24/mg and $12.06/mg in China, respectively.

Conclusion: T-DXd is more cost-effective than T-DM1 for patients with HER2-positive mBC in the US, but not in China at current drug prices.

Economic evaluation of margetuximab vs. trastuzumab for pretreated ERBB2-positive advanced breast cancer in the US and China

Objective

To assess the economic evaluation of margetuximab plus chemotherapy over trastuzumab plus chemotherapy for women with pretreated ERBB2-positive advanced breast cancer in the United States (US) and China.

Methods

Based on the SOPHIA trial, a three-state Markov model was developed to compare the cost and efficacy of margetuximab to trastuzumab for previously treated women with ERBB2-positive advanced breast cancer. The model inputs were derived from existing literature and the US life table. Primary outcomes included lifetime costs in US dollars, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER). Deterministic and probabilistic sensitivity analyses were conducted to evaluate the impact of uncertainty.

Results

The base case analyses demonstrated that margetuximab plus chemotherapy had an increasing cost of $68,132 and $20,540 over trastuzumab plus chemotherapy in the US and China, respectively, with a gain of 0.11 and 0.09 QALYs both favored margetuximab. The ICERs for two treatment strategies were $260,176 in the US and $630,777 in China, resulting in a poor cost-effectiveness at their respective threshold of willingness to play. One-way sensitivity analyses showed that the results to be most sensitive to the price of margetuximab and that of trastuzumab. And an 11 and 82% price reduction of margetuximab would make this regimen cost-effective in the US and China, respectively.

Conclusion

In the US and China, margetuximab plus chemotherapy is not likely to be cost-effective for women with pretreated ERBB2-positive advanced breast cancer, whereas price reduction effectively improves insufficient cost-effectiveness.

Cost-Effectiveness of Apatinib and Cabozantinib for the Treatment of Radioiodine-Refractory Differentiated Thyroid Cancer

Background: The effectiveness of apatinib and cabozantinib for the treatment of radioactive iodine–refractory differentiated thyroid cancer (RAIR-DTC) has been demonstrated recently. We aimed to evaluate the cost-effectiveness of these treatments from the Chinese healthcare system perspective.

Methods: Two partitioned survival models over a 10-year horizon were built to compare the cost and effectiveness of apatinib vs. placebo and cabozantinib vs. placebo based on the clinical data from the phase 3 randomized REALITY and COSMIC-311 trials. Costs and utility data were obtained from the literature and institutional database. The incremental cost-effectiveness ratio (ICER) was calculated. One-way and probabilistic sensitivity analysis was performed to test the robustness of the conclusion.

Results: Apatinib yielded an additional quality-adjusted life-year (QALY) of 0.74 at an additional cost of Chinese Renminbi ¥44,077. The ICER was ¥93,460 (US dollar $13545)/QALY and it was below the current willingness-to-pay (WTP) threshold of ¥217341/QALY. Cabozantinib was associated with an additional QALY of 0.79 at an extra cost of ¥3,55,614 when compared with placebo, and the ICER was ¥4,52,325 ($65,554)/QALY, which was above the WTP threshold. The conclusion were robust under one-way and probabilistic sensitivity analysis. The price of cabozantinib has to drop to ¥5.87/mg (39% of the current price) for it has a 50% likelihood of being cost-effective.

Conclusion: Apatinib is cost-effective for RAIR-DTC when compared with placebo from the perspective of Chinese healthcare system. However, based on the current evidence, cabozantinib might not be cost-effective and a reduction of price is warranted.

Molecular Mechanisms, Biomarkers and Emerging Therapies for Chemotherapy Resistant TNBC

Triple-negative breast cancer (TNBC) is associated with high recurrence rates, high incidence of distant metastases, and poor overall survival (OS). Taxane and anthracycline-containing chemotherapy (CT) is currently the main systemic treatment option for TNBC, while platinum-based chemotherapy showed promising results in the neoadjuvant and metastatic settings. An early arising of intrinsic or acquired CT resistance is common and represents the main hurdle for successful TNBC treatment. Numerous mechanisms were uncovered that can lead to the development of chemoresistance. These include cancer stem cells (CSCs) induction after neoadjuvant chemotherapy (NACT), ATP-binding cassette (ABC) transporters, hypoxia and avoidance of apoptosis, single factors such as tyrosine kinase receptors (EGFR, IGFR1), a disintegrin and metalloproteinase 10 (ADAM10), and a few pathological molecular pathways. Some biomarkers capable of predicting resistance to specific chemotherapeutic agents were identified and are expected to be validated in future studies for a more accurate selection of drugs to be employed and for a more tailored approach, both in neoadjuvant and advanced settings. Recently, based on specific biomarkers, some therapies were tailored to TNBC subsets and became available in clinical practice: olaparib and talazoparib for BRCA1/2 germline mutation carriers larotrectinib and entrectinib for neurotrophic tropomyosin receptor kinase (NTRK) gene fusion carriers, and anti-trophoblast cell surface antigen 2 (Trop2) antibody drug conjugate therapy for heavily pretreated metastatic TNBC (mTNBC). Further therapies targeting some pathologic molecular pathways, apoptosis, miRNAS, epidermal growth factor receptor (EGFR), insulin growth factor 1 receptor (IGF-1R), and androgen receptor (AR) are under investigation. Among them, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and EGFR inhibitors as well as antiandrogens showed promising results and are under evaluation in Phase II/III clinical trials. Emerging therapies allow to select specific antiblastics that alone or by integrating the conventional therapeutic approach may overcome/hinder chemoresistance.

A New Kid on the Block: Sacituzumab Govitecan for the Treatment of Breast Cancer and Other Solid Tumors

Human trophoblast cell-surface antigen-2 (Trop-2) is a membrane glycoprotein involved in cell proliferation and motility, frequently overexpressed in epithelial tumors. Thus, it represents an attractive target for anticancer therapies. Sacituzumab govitecan (SG) is a third-generation antibody-drug conjugate, consisting of an anti-Trop-2 monoclonal antibody (hRS7), a hydrolyzable linker, and a cytotoxin (SN38), which inhibits topoisomerase 1. Specific pharmacological features, such as the high antibody to payload ratio, the ultra-toxic nature of SN38, and the capacity to kill surrounding tumor cells (the bystander effect), make SG a very promising drug for cancer treatment. Indeed, unprecedented results have been observed with SG in patients with heavily pretreated advanced triple-negative breast cancer and urothelial carcinomas, and the drug has already received approval for these indications. These results are coupled with a manageable toxicity profile, with neutropenia and diarrhea as the most frequent adverse events, mainly of grades 1-2. While several trials are exploring SG activity in different tumor types and settings, potential biomarkers of response are under investigation. Among these, Trop-2 overexpression and the presence of BRCA1/2 mutations seem to be the most promising. We review the available literature concerning SG, with a focus on its toxicity spectrum and possible biomarkers of its response.